Under reamer



J. T. PHIPPS UNDER REAMER Oct. 8, 1957 2 Sheets-Sheet. 1

Filed March 29, 1954 INVENTOR. tray/v I: PH/PPS, BY

W/ MZ Oct. 8, 1957 J. T. PHIPPS UNDER REAMER Filed March 29, 1954 II I I IIIIIII 2 Sheets-Sheet. 2

INVENTOR.

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United States Patent UNDER REAMER John T. Phipps, Wilmington, Calif.

Application March 29, 1954, Serial No. 419,492

12 Claims. (Cl. 255-75) This invention has to do with an under reamer, that is, with a reaming tool for use in a well as, for instance, in the course of boring or enlarging the well, and it is a general object of the invention to provide a simple effective dependable tool of this character. Under reamers have long been employed in wells and it is common to provide such tools having cutters designed to be shifted or expanded in a well to effect the desired under reaming operation. The tool of the present invention is of this general class and is intended to be operated by rotation as, for instance, by means of a drilling string.

It is a general object of this invention to provide an under reamer of the general character referred to having a simple practical improved construction wherein elongate relatively movable cutters are provided having their lower end portions carried by pivot pins, while their upper end portions are carried by blocks shiftable in or relative to the body to spread the upper end portions of the cutter, and adapted to be positively operated or spread by Wedging action.

It is another object of this invention to provide an under reamer of the general character referred to wherein the blocks carrying the upper ends of the cutters are of simple compact form supporting the upper ends of the cutters in line diametrically of the body of the tool and having wedging engagement with abutments fixed in the body, which abutments have oppositely disposed inclined faces serving to positively operate the blocks oppositely to effect the desired spreading of the cutters.

It is another object of this invention to provide a simple practical improved under reamer construction providing a practical formation, arrangement and accommodation of parts in that portion of the structure where the blocks carrying the upper ends of the cutters are located in the body and are cooperatively related to abutments in the body to efiect spreading of the blocks and, consequently, the cutters when the blocks are moved relative to the abutments.

Another object of the invention is to provide a simple practical improved under reamer construction wherein the lower ends of the cutters pivotally coupled to a head are adapted to be operated by a fluid pressure actuated mechanism located at the lower end portion of the tool.

Another object of the invention is to provide a simple practical improved under reamer construction providing for effective delivery of circulating fluid at the lower end of the tool and for effective distribution of circulating fluid to the cutters when the cutters are expanded and in operating position.

The various objects and features of my invention will be fully understood from the following detailed description of the typical preferred forms and applications of my invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. l is a view illustrating a reamer embodying the present invention carried by a drilling string and located in a well bore, the cutters of the under reamer being retracted pr collapsed for free passage of the tool through 2,809,015 Patented Oct. 8, 1957 the bore. Fig. 2 is a view similar to Fig. 1 showing the cutters of the tool expanded or in operating position and illustrating the under reaming action gained by means of the tool. Fig. 3 is an enlarged longitudinal view of the under reamer showing parts thereof broken away to illustrate details of construction, showing but one cutter and the block thereto at the upper end thereof. Fig. 4 is a plan section taken as indicated by line 4-4 on Fig. 3, showing the general relationship of the blocks provided in the body carrying the upper ends of the cutters and showing the two cutters in the collapsed or retracted position. Fig. 5 is a transverse sectional view taken as indicated by line 5-5 on Fig. 3. Fig. 6 is a plan section taken as indicated by line 6-6 on Fig. 3. Fig. 7 is a transverse sectional view taken as indicated by line 7-7 on Fig. 3. Fig. 8 is a longitudinal view of the structure taken substantially as indicated by line 8-8 on Fig. 3. Fig. 9 is an enlarged detailed sectional view illustrating one of the cutters, its connection to the head supporting it at its lower end and its connection to the block supporting it at its upper end. Fig. 10 is a plan sectional View indicated by line 10-10 on Fig. 9. Fig. 11 is a view similar to a portion of Fig. 3 showing the two cutters in the out or fully expanded operating position, and Fig. 12 is a plan section of a modified form of the invention showing the cutters intermeshed.

The under reamer as provided by the present invention is intended for operation in a well bore W and may be carried by a drilling string S to the desired position in the well and to be there rotated after having been expanded to effect under reaming 10 of the bore. In the case illustrated the under reamer is carried by a tubular drilling string S carrying well fluid under pressure, and the string is adapted to be rotated to gain the desired under reaming action after the cutters have been expanded. In the particular case illustrated the string S extends down through a well casing C to support the reamer below the lower end of the casing where the Well bore is open.

The tool as provided by the present invention includes generally an elongate rigid body A characterized by an elongate transverse opening 11 adapted to carry other elements of the structure as will be hereinafter described. Cutters B, preferably two like cutters, are carried in the opening 11 and are adapted to be operated between an in or collapsed position where they are retracted and within the opening 11, and an out or expanded operating position where the cutters project a substantial distance from the exterior of the body A. A mounting meansD mounts the cutters for operation relative to the body, and in accordance with the invention, holds the cutters at or by means of their lower ends. A guide means E is provided at the upper ends of the cutters and suitably carries the upper ends of the cutters and releases these parts of the cutters from the body for the desired shifting of the cutters relative to the body. Spreading means F serve to positively operate or spread the upper ends of the cutters apart or outwardly so that they project in the desired manner from the body as the cutters operate from the retracted position to the operating position. Power means G is provided to operate the mounting means D carrying the cutters B, and the structure further includes various other elements or features of construction as will be hereinafter pointed out.

The body A is an elongate element, preferably a rigid unit, and it is adapted to be connected to a drilling string S or the like, as by means of a pin coupling 20. The body may be round or substantially round in cross section, is of such length as to accommodate the various elements of the tool as will be hereinafter described, and it is preferably of such size as to be freely operable through a well casing C or into a well bore W to the position where the under reaming is to be done.

The body A in the form shown in the drawings includes, an upper end portion 21, a lower end portion 22, and a middle portion 23. The opening 11 provided in the body to accommodate the cutters B is located in the middle portion 23 of the body. The opening 11 is an elongate slot-like o ening extending parallel with the body and transversely of the body. The opening 11 is of substantial length, as is shown in the drawings, and it extends centrally through or transversely of the body to, in effect, divide the middle portion 23 of the body into like spaced leg portions X. The walls 26 of the opening 11 as formed by the inner opposed sides of the leg portions X are preferably flat parallel parts as shown throughout the drawings, and they are spaced a substantial distance apart establishing the opening 11 of such width as to accommodate the cutters and elements of means D, E and F as will be hereinafter described.

In accordance with the present invention there are two like cutters B and these are located at or confined in the middle portion 23 of body A and are accommodated by the opening 11 above described. In practice, the cutters B are preferably alike and in carrying out the present invention they can be varied widely as to length, diameter, etc.. as circumstances require.

Each cutter B is shown as including, a toothed sleeve or cutting part 30 carried on a stem 31 throu h suitable anti-friction bearing means 32. In the particular case illustrated, the sleeve 30 is provided with a central longitudinal bore 33 that extends through the sleeve from one end to the other. and the sleeve is provided at its exterior with cutting teeth 34. The exterior of the general form of the sleeve may be varied as desired. however, in the preferred construction the exterior of the sleeve is round in cross section and is uniform in size and shape except at i the upper end portion of the sleeve where it is somewhat tapered or inwardly convergent as shown in the drawings. The tapered or convergent end of the sleeve is fastened to be substantially parallel with the well bore in which the tool is operated when the tool is expanded and being operated to under ream.

As shown in Fig. 12 of the drawings, the cutting teeth 34' may be so designed and the cutters so proportioned that the teeth 34' of the two cutters mesh. By allowing the teeth 34 to intermesh when the under reamer is col lapsed, the cutters 30' may be made substantially larger in diameter resulting in a rugged and more effective structure.

In the construction illustrated the stem 31 extends completely through the sleeve 30 and has end portions projecting beyond the ends of the sleeve. A fixed collar or flange 35 on one end portion of the stem retains the sleeve, and a detachable stop collar or split ring 36 on the other end portion of the stem retains the sleeve. The sleeve is effectively held by the collar or stops 35 and 36 so that it does not shift longitudinally of the stem.

In practice, any suitable anti-friction bearing means may be provided to support the sleeve 30 on the stem. In the drawings the portion of the stem within the sleeve is shown provided with grooves or race ways 37 carrying anti-friction members in the form of rollers 38. Further in the structure illustrated, seals 39 are provided between the stem and sleeve at the end portions of the assembly to retain lubricant for the bearing means and to prevent foreign matter from entering between the stem and the sleeve to contaminate the bearings.

The mounting means D supports the cutters B at or from the lower ends thereof, and in the construction illustrated it includes, a head 40 in the opening 11, a stem 41 depending from the head and slidably carried by the body, and coupling members 42 mounted on the head 40 by pivot pins 43, and connected to or with the lower end portions of the stems 31 of the cutters.

The head 40 is located in the lower end portion of the body opening 11 and is guided by and between the walls 26 of the opening 11 for movement lengthwise of the body or vertically in the opening 11. The stem 41 is fixed to and rigid with the head 40 and depends therefrom. In the case illustrated the stem 41 is slidably carried in an opening 45 provided centrally in the lower end portion 22 of the body. The unit or assembly formed by the head 40 and stem 41 is movable vertically between a down position as shown in Fig. 3, where the head is at the lower end of opening 11, and an up position such as is shown in Fig. 11 where the head is spaced a substantial distance above the bottom of the opening 11 while the stem is still maintained in sliding engagement in the opening 45 guiding the head in the opening.

In the preferred arrangement, as where there are two cutters B, the cutters B are side by side and their lower ends or lower end portions, which are always in the opening 11,, are spaced apart transversely of the body in the same direction that the opening 11 extends transv versely through the body. The coupling members 42 of means D are provided on the lower end portions 50 of the stems 31, and in the case illustrated each member 40 has a socket 51 receiving an end portion 50 of the stem. The socket 51 and portion 50 are provided with registering annular grooves 53 and 54 respectively, and retainers in the form of balls 52 releasably retain the stem portion 58 in the socket 51.

There is a pivot pin 43 for each coupling member 42 and each pivot pin is carried by and extends between lugs projecting up from the head 40. The manner in which each pivot pin 43 is carried by its supporting lugs 55 and carries a member 42, is clearly illustrated in Figs. 3, 9 and 11 of the drawings.

The pivot pins 43 are carried by the supporting lugs 55 so that these pins are parallel with each other, are correspondingly located lengthwise of the body A and are spaced apart laterally of the body in the direction that the opening 11 extends laterally through the body. The lateral spacing of the pivot pins 43 is such that the construction just described serves to mount or hold the lower ends of the cutters B with these parts of the cutters in the opening 11, and in side by side relation in opening 11 immediately above the head 40.

The guide means E provided at the upper ends of the cutters B and serving to control or guide the movements of these parts of the cutters includes blocks 60 mounted on or coupled to the upper ends of the cutters B and carried by the body A in the upper end portion of the opening 11. There is a block 60 for each cutter B and the two blocks 60 are in side by side relation in the opening 11, and together extend across the opening from one wall or side 26 to the other, as will be apparent from consideration of Figs. 4, 5 and 6 of the drawings. The blocks 60 have base portions 61 of substantial width that have flat outer sides 62 opposing the fiat walls or sides 26 of the opening 11. The base portions 61 of the blocks are spaced a substantial distance apart, and the blocks have transversely disposed body portions 63 projecting from the base portions and overlapping or overlying each other centrally in the opening 11, as clearly illustrated in Figs. 4 and 6 of the drawings.

The bodies 63 of the blocks are side by side laterally of the body in the direction that the opening 11 extends through the body, as clearly shown in Fig. 6. The bodies 63 of the blocks have sockets 65 entering into them. from their bottoms and outermost sides, and tongues 66 on the upper ends of the stems 31 of the cutters extend into the sockets 65 where they are pivotally coupled to the blocks or are retained by pivot pins 67. In the preferred arrangement the tongues 66 and the sockets 65 receiving the tongues are spaced apart laterally in the direction that the opening 11 extends through the body, and these parts are in linediametrically 'of the body so that the upper end of one cutter B is diametrically opposite the upper end of the other cutter.

In accordance with the present invention the blocks 60 are mounted in or carried by the body A to move relative thereto in a predetermined manner and against displacement from the body. In the case illustrated each block 60 has one or more ribs 70 projecting from the outer side 62 thereof, and the ribs are slidable in guideways 71 provided in the faces or walls 26 of opening 11. In the case illustrated each base 61 has two spaced parallel ribs '70 and each face or wall 26 of opening 11 has corresponding guideways 71. The guideways 71 in each wall 26 are pitched or inclined relative to the longitudinal axis of the tool, and in the case illustrated the two guideways 71 in each wall 26 start at or are adjacent the upper end 73 of the opening 11, adjacent one side of the body and extend down in the opening 11 and inward or towards the opposite side of the body to finally terminate and open at the opposite side of the body at a point well below the upper end 73 of the opening 11. The guideways in the two walls 26 are alike but oppositely pitched.

The parts thus far described are arranged in proportion so that when the head 40 is at the lower end of its stroke or is adjacent the lower end 75 of the opening 11, the cutters B are substantially parallel with body A and are substantially confined to or wholly contained within the opening 11 of body A, while the blocks 60 holding the upper ends of the cutters are side by side with the bodies 63 of the blocks abutting or closely approaching each other centrally of the structure. The blocks in the position just described are well below the upper end 73 of the opening 11. The positioning of the cutters just referred to is the retracted or collapsed positioning, in which case the under reamer is in condition to be freely operated through a well casing or a well bore as desired.

With the guideways and blocks 60 related as above described, upward movement of head 40 from the position shown in Fig. 3, for instance, to a position such as shown in Fig. 11, results in the blocks 60 moving upwardly in opening 11 guided by the ribs 70 operating in the guideways '71 so that the blocks move apart or oppositely and laterally of the body until they are spaced a substantial distance apart and are stopped against the upper end 73 of opening 11. The part 73 defining the upper end of opening 11 thus serves as a'stop for the upward and outward movement of the blocks 60, and the construction is such that when the blocks are thus stopped they are still effectively held by and retained in the opening 11 of the body, while the parts of the blocks having the sockets 65 therein and carrying the tongues 66 project laterally from or beyond opposite sides of the body and thus support the upper ends of the cutters B in a spread or spaced relationship as shown in Fig. 11.

When the mechanism is operated in the opposite manner, that is, the lower end of the head 40 is moved from the position shown in Fig. 11 to that shown in Fig. 3, the blocks 60 move down and in causing retraction or collapse of the cutters.

The spreading means F provided by the present invention serves to positively operate or spread the blocks 60 as they are moved up from the position shown in Fig. 3 to that shown in Fig. 11. In accordance with the invention the means F involves or provides abutment 80 located in the opening 11 at the upper end portion thereof and, in effect, depending from the top wall 73 of opening 11 and extending between the side walls 26 of opening 11. The abutment 8t) converges transversely of the body in the direction that the opening 11 extends through the body as it projects down from wall 73 of opening 11, with the result that the abutment has opposite sides facing in opposite directions and outwardly or radially of the body. In accordance with the invention one block 60 is adapted to engage and cooperate with one of these sides of the abutment, while the other block engages and cooperates with the other side of the abutment. In accordance with the invention the pitch or inclination of the said opposite sides of the abutment 80 is the same as or corresponds to the pitch or inclination of the guideways 71.

In the preferred construction at one side of abutment and adjacent one wall 26 of opening 11, there is an inclined side wall 81 of the abutment positioned to be engaged by edge 82 of the base 61 of one block, and there is a correspondingly inclined inner wall 83 parallel with wall 81 and positioned to be engaged by the side or edge 85 of that block simultaneously with edge 82 with wall 81. The parts or walls 82 and 85 of the block cooperating with the pair of walls 81 and 83 are pitched or inclined and are parallel with each other as shown in Fig. 3 so that they engage in the walls 81 and 83, respectively, to be simultaneously supported by or in wedging engagement therewith. Since the walls 81 and 33 are parallel with the guideways 71 as each block 60 is guided in its movement to move up and out as above described, there is by reason of engagement of the block with the abutment a positive wedging action operating on the block completely across the block in a direction transverse of the block and acting directly behind the socket portion or body of the block carrying the tongue of the cutter, with the result that the outward movement of the upper end of the cutter is not only guided but is positively induced or forced when the mechanism is fully actuated as shown in Fig. 11, so that each cutter supporting block 60 is securely, positively and effectively supported in the out position and thus holds its related cutter effectively in the out or working position.

The power means G provided by the invention is adapted to operate the head 40 vertically relative to the body and preferably acts on the head through the stem 41 thereof. In the preferred construction the means G is a fluid pressure actuated means or cylinder or piston mechanism. In this case the lower end portion 22 or an extension thereof has the bore or cylinder opening 91 therein and the stem 41 continues downward or has an extending portion 92 slidably operating in the cylinder opening 91 and forming the piston. In the case illustrated the stem 41 is tubular while the portion 92 forming the piston has a closure 93 closing it so that it is effective as a piston.

With the cylinder and piston mechanism just described, being located at the lower end of the tool, fluid passages 95 are provided in the tool from the upper end thereof to the lower end portion of the cylinder opening 91. In the case illustrated the upper end portion 21 is tubular and is in communication with the string S, and one or both of the leg portions 23 of the body are provided with longitudinal passage ways or branch passage ways 95 1n communication with the passages 95 in portion 21 and continuing downward in or through the lower end port1on 22 of the body to open inward at 95 to be in communlcation with the cylinder opening 91.

In the preferred construction a plug 96 is provided in the lower end of part 22, closing the lower end of the cyllnder just referred to except for a small opening or aperture 97 which serves to allow fluid from the cylinder to be discharged or jetted downwardly from the lower end of the tool. In the preferred construction a central depending ridge-like cutter 98 is provided on the plug to shield the aperture 97 and to be effective as a scraper or cutter at the lower end of the tool. Likewise, in practice, it 1s preferred that suitable cutting blades 99 be provided on the lower end portion of the portion 90 to project downwardly therefrom and radially therefrom in a manner such as is shown in the drawings.

With the construction just described fluid may be introduced to the tool through the string S to enter the cylinder at the lower end thereof and to escape through the aperture 97 and thus provide circulating fluid at the lower end of the tool without creating or generating pressure effective to cause operation of the tool from the position shown in Fig. 3 to that shown in Fig. 11. It will be 7 recognized, however, that if the supply of fluid from the string is increased, for instance,if the pressure is materially increased fluid will continue to discharge from aperture 97 and pressure will develop against the piston in cylinder 91, causing the head 40 to be moved up and operated from the position shown in Fig. 3 to a position such as that shown in Fig. 11.

In accordance with the invention it is preferred to provide means for supplying fluid to or adjacent the cutters when they are expanded or in operating position. For this purpose jet openings or apertures 100 are provided in the head 4i) between the points where the lower ends of the cutters are coupled to the head. The apertures 100 are in communication with the hollow stem 41 and its extension 92 that forms the piston. In the preferred construction there is a structure provided to control flow from the cylinder 91 into the tubular stem 41, and in the case illustrated this structure includes, a core 101 carried by plug 96 to project upwardly therefrom and to he slidably engaged in an opening 102 in the piston head 93 at all times, except when the cutters are in working position. It will be apparent from the drawings and particularly from Fig. 3, that by suitably relating the parts or by establishing a core 101 of suitable length, the opening 102 in the closure 93 remains closed until the cutters reach an up and expanded position such as that shown in Fig. 11, at which time the closure of the piston is above upper end of the core with the result that opening 102 is unrestricted. Under the conditions just mentioned, the fluid introduced into cylinder 91 is free to discharge down and out through aperture 97 and at the same time through the jets 1-00. The apertures 160 are shown as opening and discharging upwardly and substantially parallel with the inner peripheries of the cutters. Any suitable fluid distribution can be eifected by suitably locating or arranging the openings 100 or other similar openings, as desired.

It is important to observe that with the construction provided by the present invention, when the lower ends of the cutters B are coupled to the head 40 as above described, and when the upper ends of the cutters. are connected or coupled to the blocks 60 while those blocks are guided in the body as above described, the working parts cannot become separated from the body or displaced in a manner to become loose or free in the well in which the tool is operated. From a consideration of Fig. 3 it will be observed that though the guideways 71 open downwardly or are open at their lower ends to receive the ribs of the blocks, the blocks cannot move down from the position shown in that figure and can only move up until they engage and stop against the wall 73 of opening 11. The wall 73 is in the path of the blocks as they move upwardly and forms a stop positively limiting upward movement of the blocks as shown in Fig. 11, with the result that so long as the parts are assembled or coupled the blocks cannot get out of the guid-eways at the upper ends thereof.

Furthermore, it will be observed from a consideration of Fig. ll, that when the structure is in operating position the lower ends of the cutters are held in the body opening lll by means of the head 4-0 which is eflectively guided or braced between the walls 26 of opening 11, while at the same time being effectively guided and supported by the stem 41 which projects up from and remains guided by the body portion 22.

With the construction provided final assembly of the principal working parts may be completed by introduction of the ends 56 of the stems 31 into the sockets 51 followed by placement of the balls 52 so that they retain the ends 50 in the sockets. The balls 52 are retained by a suitable plug 52. it will be noted in the drawings, that the plugs are shown as threaded members. With the construction provided a release or unlocking of the mechanism can be effected by removal of the balls 52 followed by displacement of the stem ends 50 of the sockets 51.

With the construction provided by the invention the tool can be freely operated in the well to the position where the under reaming is to be carried out whereupon circulating fluid can beintroduced through the string S to effect operation of the structure from the position shown in Pig. 3 to that shown in Fig. 11. It is notable that once the operation or spreading of the cutters has been started so that the upper end portions of the cutters are in pressure engagement with the wall of the well bore, downward pressure on the tool will result in continued spreading of the cutters until they reach the full working position shown in Fig. 11. This operation of the cutters can be employed to supplement that made by fluid pressure as above described.

It is important to observe that when fluid pressure in the operating means is relieved or released the weight of the principal parts tends to cause return of the cutters from those shown in Fig. ll to that shown in Fig. 3, and if the return does not result from the weight of parts, elevation of the tool as by lifting of the string S can be resorted to and continued until the cutters reach an obstruction or well part resisting or retarding their upward movement, whereupon collapse or retraction will occur.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims:

Having described my invention, 1 claim:

l. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

2. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivota'lly holding the lower ends of the cutters in the opening for movement longitudinally of the body, the shiftable mounting means including a head in the opening adapted to move longitudinally thereof, operating means adapted to move the head lengthwise of the opening, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

3. An under reamer including, an elongate vertically disposed body having an elongate longitudinaHy disposed opening extending transversely therethrough from one side thereof to the other, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, the shiftable mounting means including a head in the opening at one end portion thereof and adapted to move longitudinally thereof, fluid pressure actuated operating means in the body adjacent said end portion of the opening and adapted to move the head lengthwise of the opening, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite direction in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

4. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, said shiftable mounting means supporting the cutters on parallel axes spaced apart transversely of the body in the direction that the opening extends transversely of the body, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

5. An under reamer including, an elongate body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, the opening having opposed side walls with guideways therein inclined relative to the longitudinal axis of the body, the guideway in one wall being inclined oppositely to that in the other wall, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks with ribs thereon slidably engaged in the guideways, the blocks pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to po sitions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

6. An under reamer including, an elongate vertically disposed body having an elongate opening extending transversely therethrough from one side thereof to the other, the opening having opposed side walls with guideways therein inclined relative to the longitudinal axis of the body, the guideway in one wall being inclined oppositely to that in the other wall, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks with ribs thereon slidably engaged in the guideways, the blocks pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship, the abutment having inclined block operating walls parallel with said guideways.

7. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks slidably carried by inclined guideways in the body and pivot pins carried by the blocks and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

8. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, the opening having opposed side walls with guideways therein inclined relative to the longitudinal axis of the body, the guideway in one wall being inclined oppositely to that in the other wall, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacently and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks with ribs thereon slidably engaged in the guideways, the blocks pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the gui'deways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship, the body having a wall defining an end of the opening and the guideways extending to said wall to carry the blocks to positions where they are spaced apart and stopped by said wall.

9. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, the body having a lower end portion projecting beyond the lower end of the opening and having a longitudinal bore therein, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening to occur adjacent and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, and including a head in the opening pivotally carrying the cutters and a stem depending from the head and slidably engaged in said bore, the body having a longitudinal passage therethrough extending from the upper end of the body to said bore and adapted to supply fluid to the bore to force the stern upward therein, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship.

10. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, the body having a lower end portion projecting beyond the lower end of the opening and having a longitudinal bore therein, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, and including a head in the opening pivotally carrying the cutters and a tubular stem depending from the head and slidably engaged in said bore, the body having a longitudinal passage therethrough extending from the upper end of the body to said bore and adapted to supply fluid to the bore to force the stem upward therein, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends or the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship, the lower end portion of the body having an aperture therein. to pass fluid from the bore and the head having an aperture therein in communication with the tubular stem engaged in the bore and adapted to introduce fluid from the bore into said opening.

11. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, the body having a lower end portion projecting beyond the lower end of the opening and having a longitudinally bore therein, two like elongate cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening and substantially parallel with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, and including a head in the opening pivotally carrying the cutters and a tubular stem depending from the head and slidably engaged in said bore, the body having'a longitudinal passage therethrough extending from the upper end of the body to said bore and adapted to supply fluid to the bore to force the stem upward therein, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship, the lower end portion of the body having an aperture therein to pass fluid from the bore and the head having an aperture therein in communication with the stem engaged in the bore and adapted to introduce fluid from the bore into said opening, there being a core in the lower end portion of the body and the tubular stem having a ported closure at its lower end passing fluid to the aperture in the head and closed by the core when the head is in a down position.

12. An under reamer including, an elongate vertically disposed body having an elongate longitudinally disposed opening extending transversely therethrough from one side thereof to the other, two like elongate toothed cutters arranged side by side in the opening at opposite sides of the body to have a collapsed position within the opening and substantially parallel with and intermeshed with each other, a shiftable mounting means pivotally holding the lower ends of the cutters in the opening for movement longitudinally of the body, guide means including two like blocks slidably carried by inclined guideways in the body and pivotally carrying the upper ends of the cutters, the blocks being held in the opening by the guideways and being adapted to move up and out in opposite directions in the opening and thereby spread the upper ends of the cutters to positions where they project from said opposite sides of the body, and an abutment in the body adapted to be engaged by the blocks when moved to the upper end of the opening and to cooperate with the blocks to positively hold them in spaced relationship, each cutter including an elongate stem having one end carried by the shiftable mounting means and the other end carried by one of the blocks of the guide means, a sleeve on the stem and having teeth on its exterior, and anti-friction bearing means rotatably supports the sleeve on the stern.

References Cited in the file of this patent UNITED STATES PATENTS 

